Long range weather forecast for the Western Isles – 21st November

Welcome to our long range forecast for the Western Isles. This is our twice weekly update covering up to two ahead. We look at trends and patterns. Usually posted on a Thursday and Sunday.

Please note there is not a lot of accuracy for this kind of time frame. Anything beyond 4/5 days out becomes really difficult and subject to change so we will be looking at trends. Mainly take with a large vat of salt. We will be using the main two computer models for this. The ECMWF ( European Centre for medium range weather forecasts) which is based in Reading and the GFS (Global forecasting system) which is the American based global model.

This comes from the GFS 06z run and ECMWF 00Z run. I will refer to EC to save on typing.

EC – Thursday 25th November to Tuesday 30th November

So the EC is suggesting that for Thursday a cold airflow sets up across the UK. For us in the Western Isles, we are going to see a cold wintry airflow across the UK. A low pressure moving far to the North of the UK will bring heavy rain and stronger winds for later in the day on Thursday. For Friday the low pressure slides Southwards into the North Sea bringing wintry showers and blustery winds for us in the Western Isles. Into Saturday the low pressure is still out in the North Sea a broad area. This will feed further wintry showers across the Western isles. Sunday and the showers gradually ease becoming drier and brighter with sunshine later. Low pressure brings further rain later in the day. Monday further rain heavy to start the day before becoming showers later in the day. Brisk winds. Tuesday low pressure moves past Shetland this will feed rain and showers across the Western Isles turning wintry at times.

GFS  – Thursday 25th November to Saturday 4th December

So the GFS is suggesting for Thursday that high pressure sits across the UK but a brisk airflow and wintry showers will move across the Western Isles. Friday a deep and vigorous area of low pressure moves down from the North bring strong winds possibly severe at times with rain and wintry showers heavy at times. Saturday high pressure builds in across the UK fine an dry day for us in the Western Isles but rain becoming wintry at times will move in later in the day. Sunday some overnight rain clears away to a mainly fine and dry day with sunshine and cloud. Monday high pressure sits to the South West of the UK but bands of rain and showers will move across the Western Isles heavy at times. Tuesday a brisk airflow across the UK will bring rain and showers across the UK. For the final four days of the time period, further rain and showers will move across the islands. Wintry at times before a deeper area of low pressure moves in later in the week.

Thanks for reading any feedback is welcome. Featured image from Magz Macleod

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